pgsql-bugs@postgresql.org writes:
> We are having a problem with our pg_clog files disappearing after a
> vacuum command is run.
VACUUM is supposed to remove no-longer-needed pg_clog files; space
reclamation is what it's all about, after all. Your problem is more
correctly thought of as "there shouldn't be any more references in my
database to old transaction numbers, once VACUUM is done".
We just today identified and fixed a problem that might allow old
transaction references to escape, but that bug could only be tickled if
a database crash occurs shortly after a VACUUM FULL. Unless you are
crashing your server on a routine basis, it seems like that doesn't
describe your problem.
Can you provide a self-contained script to provoke the problem you are
seeing? Or let someone into your system to examine things in detail?
regards, tom lane